What 29 CFR 1926.52 requires (plain English)
29 CFR 1926.52 limits construction workers' exposure to occupational noise. It requires protection against the effects of noise whenever sound levels exceed those in Table D-2 of the section, whose baseline is a 90 dBA permissible exposure limit for an 8-hour day, with shorter permitted durations as the level rises.
Critically, the standard sets a hierarchy: when employees are subjected to sound levels above the Table D-2 limits, feasible administrative or engineering controls must be used first, quieter equipment, mufflers, barriers, isolation, or rotating workers out of high-noise areas. Only when those controls fail to bring exposure within the limit may personal hearing protection be relied on to make up the difference, and a hearing conservation program is required where exposures warrant it.
1926.52 is the construction counterpart to general industry's 1910.95, sharing the 90 dBA permissible level. The two apply the same controls-before-PPE philosophy and the same recognition that noise-induced hearing loss, once it occurs, cannot be reversed.